In order to hard reset a BenQ-Siemens SL91, you should perform the following steps.

Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
BenQ-Siemens SL91 device will be brought back to the default configuration of a brand new device.


1. Turn the phone off.


2. Using keyboard, type in this sequence - *#9999#
3. The phone will now restart.